Applies To Product(s): AutoPIPE Version(s): ALL; Environment: N/A Area: Settings Original Author: Bentley Technical Support Group Date Logged & Current Version March. 2017 11.00.00.22 Problem: How does "Use corroded thickness in all analysis" on Edit Model options dialog different from "Use nominal thickness" on Results Model Options dialog? Solution: These two options are for different things. " Use corroded thickness in analysis " in Edit Options was meant for determining pipe stiffness matrix, like EA/L, 3EI/L3, etc. Usually the higher the pipe stiffness the more the moment and is conservative. After changing this setting. the model should be re-analyzed. " Use nominal thickness " in Result Options was meant in computing stresses. Once the moment is computed the stress is calculated as M/Znom or M/Zcor. Zcor will give higher stress. After changing this setting and re-analyze the system, notice that the moments have not change. The typical approach in most piping codes is to use nominal in analysis (Edit) and use corroded in stresses (Result) to give most conservative results. The result option is confusing often as there are different stresses, like hoop, expansion, sustained, occasional and some codes require corroded for some but not others. For this reason we have a table in the online help to show what happens for each code for different stress types. In v9.4 we will add a separate option for hoop stress. "Use nom thk for hoop". See AutoPIPE help for complete details on these settings. See Also Tools> Model Options> Edit settings Bentley AutoPIPE
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